<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    .demo[style] {
        background: yellow !important;
    }

</style>

<body>
    <div class="demo" style="background: red;">
        The inline styles for this div should make it red.
    </div>
</body>

</html>